Americans are changing religions – or giving up religious affiliations altogether – at a faster rate than ever before, reflecting the large number of choices in the faith marketplace, according to one of the most comprehensive surveys of U.S. religion released Monday.

More than a quarter of adult Americans have left the religion they grew up with, according to the Pew Forum on Religion and Public Life.

And if the figure included Protestants switching to different Protestant denominations, it would climb to 44 percent of adult Americans.

Meanwhile, about 16 percent of U.S. adults claim no religious affilation at all – about twice the number who were raised with no affiliation as children.

“This report documents a high level of change in religious affiliation over the lifetime of adult Americans,” said study coauthor John Green.

“This dynamism reveals the competitiveness of the religious marketplace in the United States.”

The organization surveyed more than 35,000 adults, and study authors said they believe the level of change in American religion is a reflection of the increased number of choices and mobility in society.

Other religious experts agreed, saying it is clear that Americans are overwhelmed with religious choices, just as they are in other aspects of modern life.

Many Americans also have developed distrust of large, established organizations – whether it is government or religion, said religion professor Donald E. Miller, executive director of the Center for Religion and Civic Culture at USC.

“Particularly in the post-1960s period, where notions of authority started to diminish, and there was more emphasis on personal autonomy, individuals felt it was their right to pick and choose among available options,” Miller said.

“And as the report accurately states, there are literally hundreds of options. So one no longer feels obligated in most instances to preserve the religious tradition of one’s parents or grandparents.”

The survey also found that the United States is for the first time about to become a minority Protestant country. The number of adults who call themselves Protestant stands at about 51 percent, down from when it was nearly two-thirds in the 1980s.

Green noted this is significant because the country was primarily founded by Protestants and has been dominated by them through much of its political history.

“So much of the values and institutions in American public life came out of Protestantism, particularly mainline Protestantism,” Green said.

“As those groups are replaced, we’re likely to see a change in those institutions and the cultures that support them.

The survey also found a large number of people are leaving the Catholic Church, but the church’s numbers remain steady because of a growing Latino immigrant population that is predominantly Catholic.

The study’s authors said that while Protestants outnumber Catholics 2-to-1 among native-born Americans, the reverse is true for the immigrant population.

Green said if all the people who were raised Catholic remained in the church as adults, then the Catholic population would be almost one-third of the nation’s total, rather than one-fourth.

Almost a tenth of the nation’s adults are former Catholics, he said.

Mormons and Muslims have the largest families, with more than 20 percent of Mormons and 15 percent of Muslims having three or more children at home, the study found.

And it also found that Jews and Hindus are more likely to report a higher degree of education and income than the overall population.

Some religious leaders in the Los Angeles area were not surprised by the study. They said they have experienced the same level of change within their own communities.

Dudley Rutherford, senior pastor of the Shepherd of the Hills Church in Porter Ranch, a nondenominational Christian church with about 12,000 members, said the growth of his own organization is a reflection of this greater trend in society.

Some new members have joined his church, he said, out of skepticism about a particular denomination, as well as a dislike of the heavily ritualized nature of some religions.

“We don’t have the rituals, the formalism. We stand and worship and sing a few songs. We study the word of God and apply the Bible to everyday living. We’re not wearing robes and we’re not chanting and we’re not doing the incense thing,” he said.

“I think the ritualism and the formalism is not what is going to meet that inner hunger in everyone’s heart.”

Rabbi Mark S. Diamond, executive vice president of the Board of Rabbis of Southern California, said he has seen the same trend, both within Judaism and in society at large.

At the same time, he said, the diversity within established religous groups is also changing. For example, he said, particularly in places like Los Angeles and the Bay Area, there are growing numbers of African-Americans and Asians converting to Judaism.

“The stereotype of Jewish identity in this country is pretty much white, Caucasian Jews, most of whom trace their ancestry back to Europe,” Diamond said.

“That’s no longer the case necessarily. I think that ethnic and religious cultural diversity is very much a welcome phenomenon.